Nikon heard photographers and have made the eyepiece for the D5 very difficult for it to accidentally come off on its own. You have to now depress the two button on the left and right side at the same time to unscrew the eyepiece. Its truly locked into place and isn’t accidentally coming off. In fact, I’ve had a few folks write in and have personally experienced how difficult it can be to get the eyepiece unscrewed even when you depress the two buttons. Found a real simple solution that I mentioned in my last Podcast. Depressing the two button also permits the DK-27 to completely slide off the D5. With it off, place it in the sun for a couple of minutes and is quickly unscrews. As one who earned sore finger tips trying to unscrew an eyepiece, this simple cure might just save you some skin.